1. Field
The present application relates to a storage medium storing an image processing program which performs an image processing on image data to be processed, an image processing device, and an image processing method.
2. Description of the Related Art
When image data generated by an imaging device such as an electronic camera is output to output equipment such as a CRT monitor and printer, gradation conversion processing using a gradation curve corresponding to the output equipment is performed to improve the appearance. If such gradation conversion processing is not performed, the appearance is marred by the flare, black floating, external light reflection, etc., of the output equipment. For gradation conversion processing, a so-called S-shaped gradation curve is used in addition to a gradation curve corresponding to the output equipment. By adjusting contrast using the S-shaped gradation curve, it is possible to obtain an output image with high contrast by the output equipment (for example, Japanese Unexamined Patent Application Publication No. 2004-222076).
Furthermore, contour enhancement processing for enhancing contrast is also performed in order to improve the appearance. The contour enhancement processing includes a method of enhancing contours by adding high-frequency components to the original image data, a method of enhancing contours using a so-called contour enhancement filter (for example, Japanese Patent No. 3512581), etc.
In the gradation conversion processing of the invention in the above-described Japanese Unexamined Patent Application Publication No. 2004-222076, while it is possible to enhance contrast, there is a case where the contrast of the bright part gradation is reduced or the dark part gradation is shadowed and blocked up. Furthermore, when gradation conversion processing using an S-shaped curve is performed on each of the R, G, B values, there used be such a problem that the hue and color saturation of each of the bright part gradation, the intermediate part gradation, and the dark part gradation change.
Moreover, the contour enhancement processing of the invention in the above-described Japanese Patent No. 3512581 used to have such a problem that when contour enhancement processing is performed with a large radius, the change in color saturation becomes conspicuous or the blown out highlights of the bright part gradation become more likely to occur.